Else, Less, ____

These brain teasers rely on your ability to recognize groups of common attributes. For each of these puzzles you'll need to figure out why the words or letters are grouped as they are. Sometimes you will be asked to pick the odd-one-out or to place a new word into the correct group.

Signmeup, ells, that is a real word. Well, I'm at least 99.9% sure because of the word ell which is the remains of a wall or the base of a wall. Something along the lines of that, I remember losing anagrams online because I forget "ell" is a word.
Great teaser!